Electric-arc lamp



(No Model I 2 SheetsSheet 1 H. H. CUTLER.

ELECTRIC ARC LAMP.

No. 482,485. Patented Sept. 13, 1892.

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H. H. CUTLER.

ELECTRIC ARC LAMP.

No. 482,435 Patented Septr13, 189 2.

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UNITED I STATES PATENT OFFICE HENRY H. CUTLER, OF \VALTHAM,MASSAOHUSETS.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 482,435, datedSeptember 13, 1892.

Application filed June 25, 1891- Serial No. 397,493. (No model.)

To all whom it may concern.-

Be it known that I, HENRY H. CUTLER, of Waltham, county of Middlesex,State of Massachusetts, have invented an Improvement in Electric Lamps,of which the following description, in connection with the accompanyingdrawings, is a specification, like letters on the drawings representinglike parts.

My invention is embodied in the feeding mechanism of an electric-arclamp adapted to be used either with a current of constant potential,such as employed when the lamp is operated in a shunt between'the mainsupplywires in the alternating-current system, or to be operated withconstant current, such as is commonly used when are lamps are placed inseries.

The feeding mechanism forming the subject of this invention comprises afeed-actuator connected with the carbon, by which the latter is fedpositively, as required, the motive power of said actuator being derivedfrom the current by which the light is produced, but not being dependentupon the resistance of the arc. The operation of the said actuator iscontrolled by a regulator, which is responsive to changes of conditionof the arc and causes the feed-actuator to be operated to feed thecarbons toward one another when the arc lengthens by burning away thecarbons, but prevents such feed from operating when the arc is of normallength. The actuator is so connected with the carbon to be fed that atthe beginning of the operation of the lamp, when the carbons are incontact, it will make a movement by which the carbons are sepa rated andthe are drawn; but in the subsequent normal operation of the lamp thefeedactnator does not separate or tend to separate the carbons, butmerely causes them to be moved together in proportion as their pointsseparate by the consumption of the carbon.

As herein shown, the actuator is a thermostatic device, its operationdepending upon the expansion and contraction of a conductor produced bythe heating ettect of the current and the cooling of the conductor Whenthe current is removed from it, and, as shown in this instance, thethermostatic device is merely a wire which operates by direct linearexpansion, such movement being very powerful, although of comparativelysmall amount, and in order to prevent too rapid movements the changes ofcondition of said thermostat are from a condition in which it carriesthe whole current to a condition in which it carries a portion of thecurrent, although it is obvious that it it is desired the entire currentmight be removed when it is desired to operate the actuator in onedirection and the entire current applied when it is desired to operateit in the other direction. The regulator is also shown in this instanceas a thermostatic device included in circuit with the are, thisconstruction being desirable when the lamp operates with constantpotential, so that the current is diminished in proportion as the arelengthens. The regulator-thermostat is also a wire operating by directlinear expansion and contraction, it being always included in circuitwith the are, so that as the arc lengthens the wire receives lesscurrent, becomes cooler, and consequently contracts, and when thecarbons ap proach, so that the arc offers less resistance, the said wirereceives more current and expands. The expansion and contraction of theregulator-thermostat is employed to operate a switch which controls thecurrent supplied to the actuating-thermostat, the mechanism being suchthat when the regulator contracts, owing to the lengthening of thearc,it causes a portion of the current to be removed from the actuator,thus causing a contraction of the actuating-thermostat, in which thepart connected with and moved by the actuating, thermostat moves in thedirection to bring the carbons nearer together, such movement beinggradual, so that no sudden changes in the are are produced.

The mechanism between the actuator and carbon is as follows: Theactuating-thermostat wire connects with a lever very close to itsfulcrum, said lever being provided with a spring that tends to pull ittightly against the wire, and consequently moves the lever in onedirection as the wire expands and yields to permit movement of the leverin the other direction when the wire contracts. The said lever isprovided with a device that engages with the carbon rod or some partconnected directly with it during its movement in one direction, but notin the other. As shown in this instance, the engaging device is a pawlor friction-dog, and it engages with a wheel which has either aroughened surface or very fine ratchet-teeth to co-operate with the saidpawl, and is connected with a winding-drum, to which is fastened and onwhich is wound a flexible support connected with the carbon, so that asthe said wheel and drum are permitted to move in one direction theflexible support is paid out and the carbon permitted to descend bygravity. Such descent of the carbon is produced by the movement of thepawl-engaginglever while in engagement with the wheel, and normally whenthe lever is movin g in the opposite direction the pawl is disengagedfrom the wheel, which is at this time prevented from turning by aretaining-pawl that operates upon it or upon another wheel similarlyconnected with the same winding-drum. The regulator, besides operatingthe switch that controls the current, also mechanically operates the twopawls, causing the retainingpawl to be disengaged, while the lever-pawlis engaged and moving downward to permit the descent of the carbon, andcausing the retaining-pawl to be engaged and the lever-pawl disengagedwhile the lever is moving upward preparatory to again engage with thewheel, so as to cause the carbon to feed again, such upward movement ofthe feed-lever taking place while the arc is of normal length and thecarbons are burning, and thus tending to increase its length.

The device by which the regulator engages with the pawls is soconstructed that when the are offers substantially no resistance, aswhen the lamp is beginning to operate, it affects the lever-pawl in theopposite way to that n which it is affected during the normal operation,in that at this time the lever-pawl is in engagement with the wheelduring the upward movement of the lever, and thus causes the arc to bedrawn.

Instead of the thermostatic devices employed to actuate the feed and toregulate the operation of the actuator electro-magnetic devices might beused for either one or both without changing the essential relations andmode of operation of the two devices, and for series lamps anelectro-magnetic device in a shuntcircuit around the are will commonlybe employed as the regulator.

Figure 1 is a front elevation of the feed mechanism and a portion of theframework and carbons of an arc lamp with the parts in one of thepositions assumed during the normal operation, the front frame-platesbeing removed; Fig.2, a plan view thereof with the upper frame-plateremoved; Fig. 3,a side elevation of the feed mechanism in the positionassumed before the arc is drawn, with front frame-plates removed; andFigs. 4. and 5, details showing portions of the working parts indifferent positions assumed in the operation of the lamp, as will beexplained.

As shown in Figs. 1 to 4, the invention is embodied in a lamp intendedfor use in an alternating current or under conditions in which theterminals of a lamp are at practically-constant potential.

The feed mechanism is supported between cross-bars a a of insulatingmaterial, the lowerone of which constitutes the upper member of thelamp-frame, which comprises the side tubes?) b and lower cross-bar 6 inwhich the lower carbon C is supported in the usual manner, the uppercarbon C being, as shown in this instance, connected with a cross-headb, which slides vertically on the side tubes 1) biand is connected byaflexible cord or band 0 with a drum 0 the rotary movement of which thuscontrols the vertical movement of the said upper carbon C. The rotarymovement of the drum 0 and consequently the feed movement of the carbonC, is controlled by an actuator comprising a lever d, pivoted at d inmetallic upright plates a a, (see Fig. 2,) extending from one to theother of the frame-pieces a 0L and acted upon by a spring d, which tendsto move the said lever in one directionas, in this instance, upward-saidlever being moved in the opposite direction by the actuator proper,shown in this instance as thermostatic in character, being a wiree,extendinga sufficient distance through the interior of the tube andmade fast at its lower end in said tube, the said wire being connectedat its upper end with a stirrup e that engages the said lever at nearits fulcrum. Thus expansion of the wire 6, which takes place when it isheated by a strong current passing through it, permits 'the lever 61 tomove upward under the strain of the spring d and the contraction of saidwire due to its cooling when said current or a portion thereof isremoved from it causes the said lever to be moved downward, thecontraction of the wire overcoming the strain of the spring (Z Theapplication of the current to the thermostatic actuator e is governed bya regulator (shown in Fig. 1 as also thermostatic in its action)comprising a wiref, fastened at its lower end in the tube 1') andconnected at its upper end with a stirrup f engaging a lever g,fulcrumed at g in the frame-pieces a a, Fig. 2, connecting thecross-bars 1 Ct at and acted upon by a spring g which moves the leverupward in proportion as the wire f expands and permits it to be moveddownward as the said wire contracts.

Before describing the mechanism by which the regulator f and its lever 9control the current which affords the motive power for the actuator eand its lever d and the mechanism by which the said lever (Z operatesthe feed of the carbon, the electric connections will be described andthe said operative mechanism described in connection with the movementsthat the actuator and regulator are caused to make.

The current enters at the usual supportinghook h, passes thence by aconductor 2 to the side post I), and down the same to the lower end ofthe wire f, and thence back through.

the said wire, which is electrically connected at its upper end by aflexible conductor 3 (a copper ribbon) with the metallic framework a, inwhich the metallic drum 0 works. The current thence passes through theflexible support 0, which is also a conductor, being, for example, athin ribbon of copper, to the upper carbon C, and thence through the areor directly to the lower carbon 0 and by a conductor 4 to the side post19 and wire e, which is connected by a flexible conductor 5 with theother supporting hook h of the lamp, thus completing the circuit throughthe carbons and arc. With the connections thus far described the wholecurrent is at all times passed through the actuator-wire which isconnected by a flexible conductor 5, with the other supporting-hook 72,of the lamp, thus completing the circuit through the carbons and are.\Vith the connections thus far described the whole current is at alltimes passed through the actuator-wire e, which would be subjected toonly such variations in current as would be produced by variations inresistance at the arc; but, as before stated, such variations are notnot relied upon to operate the wire e,butit is subjected to largervariations under control of the wire f, which is itself operated only bythe variations in current produced by the varying resistance of the arc.The variationsin the wire emight be produced by wholly cutting it out ofcircuit, so that it would receive no current at times when it was cutout, and would receive the whole currentat other times, thusmakin g verylarge changes of condition, which might be employed to do considerablemechanical work. As shown in this instance, instead of being wholly cutout of circuit when it is desired to cause it to contract, a shunt isclosed around said wire 6, said shunt consisting of another wire c whichmay be of any desired conductivity relative to that of the wire 6,according to the change in current required to operate the wire e, thesaid wire 6 for example, being of equal conductivity, so that the wire 6receives the whole or a half of the current, according as the shuntcontaining the wire e is open or closed. The said shunt includes acircuit-closer, one member 7a of which is in the form of a lever pivotedupon a bracket but insulated from the other operative parts thus fardescribed, and the other member of which is a projection k carried bythe regulator-lever g. The said members 70 k are connected by wires 6and 7, respectively, with the wire 6 and the hook 7L2, so that when themembers are in contact the current from the lower carbon and post Z)will divide between the wires 6 and e in passing to the hook 7L2, sothat the wire 6 will receive only a fraction of the current, which willbe one-half if the wiers e and e are of equal conductivity; but when themembers 70 k are separated and the shunt is open the wire 6 will receivethe whole current. Thus there will be a definite change in the currentreceived by the wire 8, according as the shunt is open or closed, whichchange will be substantially uniform at all times in the operation ofthe lamp and will produce a substantial expansion or contraction of thewire, according as the whole or a fraction of the current traverses it,and there will thus be produced upward and downward movements of thelever d, according as the shunt is opened or closed by movements of thelever g. This upward and downward movement of the lever g is caused toproduce corresponding feed movements of the carbon through theintervention of a pawl m, pivoted at m upon an insulating-piece d, fixedupon the free end of the lever (Z, and the said pawl m, co-operatingwith awheel a, connected with the drum 0 by which the carbon is lowered,the said wheel a having a roughened or toothed surface for engagementwith the pawl m.

A second pawl 19, 00- operating with the wheel at oranother similarWheeln connected with the drum, operates to prevent rotary movement ofthe drum and downward movement of the, carbon when said pawl 29 isengaged with the wheel. These pawls operate in the normal feed of thelamp as follows: The retaining-pawl p is engaged and prevents feed whilethe pawl-carrier d is moving upward, at which time the pawl m isdisengaged from its wheel, and consequently no movement of the wheel isproduced, these operations occurring while the arc is about normallength, but increasing by the burning away of the carbons. Then the pawlon is engaged with the wheel and the pawl 19 disengaged, and thepawl-carrier d is caused to move downward by the contraction of the wirea, resulting from the closing of the shunt for said wire, so that thewheel is permitted to turn and the carbon lowered by the downwardmovement of the pawl-carrier or feed-leverd, instead of being permittedto slip and feed by gravitation, as is the case in most feed devices. Itis necessary, therefore, that the regulator should cause such operationof the pawls and pawl-carrier to take placethat is, while the arc is ofnormal length and tending to increase by the burning of the carbon itmust cause or permit the pawl 19 to be engaged to prevent descent of theupper carbon, it musthold the shunt open, so that the wire will. expandand the lever d move upward, and it must cause the pawl m to bedisengaged during this upward movement, so that it will not turn thewheel in the direction to raise the upper carbon and lengthen the are bydrawing the carbons apart. Then when the arc lengthens by consumption ofthe carbon, so as to require the feed to take place, theregulating-lever 9 must cause the shunt to be closed, so as to producecontraction of the wire e and downward movement of the pawl carrier, itmust cause the pawl 71 to be engaged with the wheel, so as to permit thewheel to accompany it in this downward movement, and thus feed thecarbon, and it must cause the pawl 12 to be disengaged, so as to permitsuch movement of the drum and carbon under control of the pawl m andpawl-carrier (Z. The engagementof pawl m is governed by a lever r,pivoted at r and provided with a weight r or an equivalent tending toturn it toward the lever g. The said pawl-controlling lever 1 has acam-surface "1- that engages with a projection g on the lever g, so thatthe position of the' lever r is controlled by the position of the leverg. The lower part of said surface r is about concentric with the fulcrumof the lever g, so that the movement of the pin g along this part of thesurface r does not change the position of the lever which is providedwith another surface P, that engages with a projection m on the pawl m,the two surfaces 7" and r being so shaped that while the projection g ison the lower concentric part of the surface 7' the surface r does notbear upon the projection m and thus permits the pawl m to be inengagement with the wheel n. The lever r is provided with a projectingpart 0" at the upper end of the concentric part of the surface T andwhen the projection 9 comes against the projection r it turns theleverron its pivot, so as to force the surface r against the projectionm which throws the pawl m out of engagement with the wheel 11, as shownin Fig. 4. Thus the lever Q can swing on its fulcrum from about theposition shown in Fig. 3 to that shown in Fig. 1 Without changing theposition of the pawl-controller T, which then stands in such positionthat the lever d can make its complete movement about its fulcrum withthe pawl m in engagement with the wheel 91; but when the lever 9 movesfar enough to bring the projection g onto the part Not thepawlcontroller, as shown in Fig. 4', it causes the pawl m to be thrownout of engagement with the wheel it whatever may be the position of thelever (Z. The same projection g that governs the pawl-controllerr,or, ifpreferred, another projection on the lever 9, also controls the pawl 19,which has a long projection 19 about concentric with the path ofmovement of the projeetiong of the lever g, which in the movement fromthe position shown in Fig. 3 tonearly the position shownin Fig.1 holdsthe pawl p out of engagement with the wheel 91 as clearly shown in Fig.3. Just about at the moment when the projection 9 begins to act upon theprojecting part 0" of the pawl-controller r, so as to move the same inthe direction to disengage the pawl m from the wheel n, as shown in Fig.4, it passes off from the arm 19 of the pawl 13 and permits the latterto come into engagement with the wheel of, so that as the projection gmoves up or down from the position shown in Fig. 1 it throws the pawls mand p alternately out of engagement. These parts should be soconstructed that the one pawl will come into engagement just before theother disengages, so that the wheels 01 n will always be under controlof one or the other of the paw1sthat is, with the parts in the positionshown in Fig. 1 both pawls are engaged and a slight upward movement ofthe projection g will throw the pawl m out of engagement, leaving thepawl p in engagement, while a slight downward movement will throw thepawl 19 out of engagement and leave the pawl m in engagement. The member70 of the shunt-circuit closer in the shunt for the actuating-wire a,before mentioned, is pivoted in the end of the bracket 70 and is actedupon by a light spring 70 which tends to hold the said arm 7a projectingtoward the path of movement of the said projection k 011 the lever 9,but permits the arm 70 to yield as the said yielding projection movespast it in either direction, the said projection and arm makingelectrical contact as the projection passes. V

The operation is as follows: \Vhen no current is flowing, the parts arein the position shown in Fig. 3, the wiresfand e being contracted andholding the levers g and (Z in their lowest position. In this positionthe pawl p is disengaged from the wheel a and the pawl m is alsodisengaged from the wheel a, which may be done by a slight rise at thelower end of the surface r or by a similar rise in the lower part of thesurface T or by the stop hi as shown in Fig. 3. The wheels n n are bothleft free and the carbon C descends by gravity until it rests in contactwith the carbon 0 The shunt for the actuator is then open at 7.1 asclearly shown in Fig. 3. When the current is turned on, it will meet noarc resistance and will flow through both wires f and e, causing thesame to expand quickly. The wiref will commonly be more delicate thanthe wire 6, and will respond first to the current, causing the lever gto move up quickly, and as the arc is not yet drawn said wire f willreceive more current than under normal condit-ions of operation of thelamp, and will rise above the position at which itnormally stands toabout the position shown in Fig. 5, having passed wholly above theprojecting part 1- of the pawl-carrier, and standing opposite a recessedportion 0' above the said projecting portion, and thus permitting thepawl-controller to return toward the position that permits theengagement of the pawl m with the wheel n. The retaining-pawl 19 will inthis movement have come into engagement with the wheel 92 so as toprevent any downward movement of the feed. After the lever g has madeits upward movement, as thus described, under the expansion of the wirefor while it is still moving the lever (Z will begin its upward movementunder the expansion of the more-slowly-acting wire 6, and as the pawl mwill be in engagement during the said upward movement of the lever d thewheel a will be turned in the direction to raise the upper carbon, andthus draw the are. In order to prevent too great upward movement of thecarbon before the proper equilibrium is established, a stop is providedfor the lever (Z, shown as consisting of a number of shoulders I, on thepawl-controller r, that co-operate with a pivoted projection t on thearm (1 of the lever d. The lever cl will thus be arrested after a shortupward movement sufticient to establish the arc, and the wire 6 maycontinue to expand, as its connection with the lever d is such that theexpansion of the wire does not positively move the lever upward, butmerely permits it to be moved by the spring (Z The stop '6 is engagedwith one or the other of the shoulders 25, according to the positionthat the lever g and pawlcontroller r are in at the time when the lever(l rises to its uppermost position. If the lever g is very high it willpermit the stop to engage one of its higher shoulders and thus effectthe drawing of a longer are than takes place if the lever 9 stops in asomewhat lower position. The drawing of the arc and its subsequentlengthening as the carbons burn diminishes the current in the wiref,which will thus contract somewhat and draw the lever 9 toward theposition shown in Fig. 1, which is about the position in which the saidlever should stand for an arc of normal length, and when the parts cometo this position the normal feed of the lamp will take place, thecarbons being brought together in proportion as they are consumed, asfollows: The establishment of the are by the upward movement of thelever(1 causes a rather sudden diminution in the current of the wiref, whichwill contractand draw the lever g down from the position shown in Fig. 5through the position shown in Fig. 4 and toward the position shown inFig. 1, and the gradual lengthening of the are by consumption of thecarbons will cause a very slow movement downward, by which it will passbelow the position shown in Fig. 1, first permitting the pawl m to comein engagement with the wheel 91 while the lever 61 is still in thelifted position shown in Fig. 4 or 5, then causing the pawl p to bedisengaged from the wheel 11 so that the carbon is now supported by thepawl m, and not by the pawl n, and finally the lever 9 will move farenough down to close the circuit at k ofv the shunt for theactuating-wire, thus removing the current from the said wire, which willcontract and draw the lever d downward from the position shown in Fig. 5toward that shown in Fig. 1, lowering the upper carbon and feeding thesame. \Vhen such feed of the carbon is sufficient to bring the are backto normal length or a trifle less, the wire f receives more current,again causing the leverg to rise, this movement opening the shunt, asshown in Fig. 1, and thus causing more current to pass through the wire6, the latter to expand, and the lever d to rise; but by the time thatthe lever d begins to rise under the effect of the increased current inthe wire e the projection g has arrived on the partv' of thepawl-controller and moved the same sufficiently to throw the pawl an outof engagement with the wheel at, so that the said pawl m moves upwardwithout turning the feed wheel, which is held from running in the otherdirection by the pawl p, which, as before stated, is brought intoengagement just before the pawl in is disengaged. Thus in the normaloperation of the lamp the lever g vibrates slowly a short distance aboveand below the position shown in Fig. 1, and the lever (Z also has avibratory movement, which is controlled by and dependent upon themovement of the lever g, and although the feed is intermittent inoperation, the feed movements are very slow and gradual, and a verysteady arc is maintained.

' WVhile the devices herein shown as responsive to changes in currentare thermostatic in their nature, depending upon the heating effect ofthe current, it obviously is not essential to the operative relations ofthese parts that they should be thermostatic in their nature.

Any device responsive to slight changes in current might be substitutedfor the wire f and would be equivalent therefor, it being necessary onlythat such devices should produce a movement of the controlling device gin one direction upon an increase in the length of the arc and in theother direction upon a decrease in the length of the arc and that suchmovements should control the application of a motor-current to theactuator, which also may be any device responsive to such motor-currentand capable of producing the required movements of the lever d orequivalent part co-operating with the carbon to be fed. 4

Thethermostatic devices shown are responsive to alternate currents, andthus constitute a desirable form of instrument to be used when the lampis operated by alternating currents, while being equally effective fordirect currents.

\Vhen, as is the case with series lamps, the circuit is supplied withsubstantially-constant current, the partsensitive to the change in thearc is, as is well known, included in a shunt around the arc, so thatthe current divides between the arc and the said controlling-shunt,which commonly controls the feed direct.

It is obvious that the present invention is applicable to lamps operatedin this manner, and persons familiar with the construction and mode ofoperation of the lamp will understand readily how to connect thecontrolling and actuating device in circuit and how to construct suchcontrolling and actuating device for proper operation in series arelamps.

1. The combination of the carbons of an electric-arc lamp with afeed-actuator and a circuit-controller governing the application ofcurrent thereto and a thermal feed-regulator responsive to changes inlength of the arc and operating the said circuitcontroller for thefeed'actuator, substantially as described.

2. The combination of the feed pawl and its actuating-pawl carrier witha pawl-con- IIO troller governing the engagement of the said pawl and aregulator responsive to change in length of the arc co-operating withthe said pawl-controller, substantially as and for the purposedescribed.

3. The combination, with the carbons of an arc lamp, of a feed-actuatorcomprising a thermostatic device connected in circuit and responsive tothe heat produced by the current therein, a circuit-controller governingthe application of current to the said thermostatic actuator, and aregulator responsive to changes in length of are operating the saidcircuit-controller, substantially as described.

4. The combination, with the carbons of an electric-arc lamp, of thefeed-actuator whose

